1. Field of the Invention
The present invention relates to an IC card and a manufacturing method therefor, the IC card being formed in such a manner that a circuit board portion, on which electronic parts having various functions are mounted, is sealed in a frame with a molding resin sealant.
2. Description of the Related Art
FIGS. 1A and 1B are a plan view and a front elevational cross sectional view each of which illustrates a conventional IC card of a non-contact type having no electrode terminal for establishing an external connection. A circuit 3 is formed on one of the main surfaces of a circuit board 2 made of, for example, epoxy glass. Furthermore, electronic parts such as ICs (Integrated Circuits) 1 and communication means (for example, a transmitting/receiving coil) (omitted from the illustration) are mounted on the same main surface of the circuit board 2. The thus arranged circuit board 2 is adhered within a lower case 4a by using an adhesive, or the circuit board 2 and the lower case 4a are joined by ultrasonic welding. Then, an upper case 4b is adhered onto the lower case 4a by using an adhesive so that an outer case 4 is formed. Thus, a thin IC card is manufactured.
FIGS. 2A and 2B are a front elevational cross sectional view and a bottom view of another conventional IC card of a contact type arranged in such a manner that electrode terminals for establishing an external connection appear on the surface thereof. A projecting terminal frame 2a is integrally formed with one of the surfaces of the circuit board 2 or fastened to the same by bonding. A circuit 3 is formed on the surface of the circuit board 2. A plurality of electrode terminals 5, are formed on the outer surface of the terminal frame 2a, the plurality of electrode terminals 5 being connected to the above-described circuit 3 via through holes 6. The lower case 4a has an opening through which the terminal frame 2a is introduced so as to be engaged thereto. Thus, the circuit board 2 is bonded onto the inside of the lower case 4a so that the electrode terminals 5 appear outside on the surface of the IC card. The upper case 4b is bonded onto the lower case 4a so that the outer case 4 is formed. Thus, the IC card is manufactured.
The conventional IC cards of the above-described types are arranged in such a manner that the thickness of each of the upper and the lower plates of the outer case 4 and the gap between the components mounted on the circuit board 2 are reduced in order to reduce the overall thickness of the IC card. Therefore, a problem arises in that the IC card can be easily deformed by external pressure, causing the electronic parts to be subjected to undesirable effects. Another problem arises in that it is difficult to secure the circuit substrate 2 to the lower case 4a and to join the upper case 4b to the lower case 4a with an airtight seal between the periphery of the terminal frame 2a and the opening formed in the lower case 4a (if there is a gap, water can enter therethrough). What is even worse, the upper case 4b and the lower case 4a which have been bonded to each other can be undesirably separated from each other. In order to prevent the deformation of the IC card due to external pressure, means for injecting synthetic resin into the space in the outer case 4 must be provided.